Add specs for Refinement#import_methods and deprecation of include/pr…

…epend

core/refinement/import_methods_spec.rb

@@ -0,0 +1,34 @@
+require_relative '../../spec_helper'
+
+describe "Refinement#import_methods" do
+  ruby_version_is "3.1" do
+    context "when methods are defined in Ruby code" do
+      it "imports methods" do
+        str_utils = Module.new do
+          def indent(level)
+            " " * level + self
+          end
+        end
+
+        Module.new do
+          refine String do
+            import_methods str_utils
+            "foo".indent(3).should == "   foo"
+          end
+        end
+      end
+    end
+
+    context "when methods are not defined in Ruby code" do
+      it "raises ArgumentError" do
+        Module.new do
+          refine String do
+            -> {
+              import_methods Kernel
+            }.should raise_error(ArgumentError)
+          end
+        end
+      end
+    end
+  end
+end

core/refinement/include_spec.rb

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+require_relative '../../spec_helper'
+
+describe "Refinement#include" do
+  ruby_version_is "3.1" do
+    it "warns about deprecation" do
+      Module.new do
+        refine String do
+          -> {
+            include Module.new
+          }.should complain(/warning: Refinement#include is deprecated and will be removed in Ruby 3.2/)
+        end
+      end
+    end
+  end
+end

core/refinement/prepend_spec.rb

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+require_relative '../../spec_helper'
+
+describe "Refinement#prepend" do
+  ruby_version_is "3.1" do
+    it "warns about deprecation" do
+      Module.new do
+        refine String do
+          -> {
+            prepend Module.new
+          }.should complain(/warning: Refinement#prepend is deprecated and will be removed in Ruby 3.2/)
+        end
+      end
+    end
+  end
+end